Sealed tamperproof maximum and minimum thermometer for use particularly in brooding of chicks



21, 1937.` M. A. CAMPBELL.

SEALED TAMPERPROOF MAXIMUM AND MINIMUM THERMOMETER FOR USE PARTIGULARLY 1N BROODING OF CHICKS Filed Feb. l2, 1937 Zar/7l Patented Dec. 21, 1937 Y @UNITED .1J/STATES y y 2,102,678 `SEALED .TAMPERPRooF MAXIMUM AAun -MINIMUMTHERMOMETER nonA Use PAR- TICULARLY 1N .-BRooDING oF onions Max A. '(Jam'p'la'ell,` East ProvidencefR. I. Application :february .-12, 1937, serial No. 125,472 7 claims. (o1. "7s- 374) AMy invention-relates to .improvements in sealed tamper-proof tmaximum -and minimum ther- `mometers `:for use .particularly inthe brooding of chicks.. It has been customary `forzsellers of Achicks to lguarantee `the Ylife of the chicks for a period'of over two or three Weeks. This has involved considerable riskas all types ofy wood, coal lor electric 'brooders lare now used and they may not be operated intelligently, so as .to permitqthe temperature to rise 'above :the temperature safe for chick brooding orrto :permit it to yfall below the .temperature safe vfor chick'brooding.

An object 4of my `in-vention is to Aprovide 4a positively tamper-proof 'maximum and kminimum thermometer Ywhich :may be loanedA to the lpur- -chaser for this period zof over 'two vor three weeks, uso Ythat the S'seller may 'check up `the maximum -and minimumfreadings with .assurance that they .will not :be ytampered with and for this purpose I have provided-for any typeof'maximum or minimum thermometer `a Acasing forming a fmagnetic screen to prevent exterior magnetic tampering Vwith the :maximum 4and minimum indicating means `therein which rmay be preferably sealed with the thermometer :encased therein during vthis period and which ,mayfbezopen'ed up to per- '.mit the thermometer to; be inspected -by the-seller at the end ofthe guarantee period.

Further objects'of :my invention are to provide supplemental precautions in a Vtamper-proof -maximum and .minimum thermometer for preventing external manipulation of the .indicating means thereof. It is supplementallyknown vthat the magnetic indicators in` maximum and mini- ,mum thermometers may bek-hooked outof their true registering maximum and minimum posi- `tionsby forcibly tapping theend of the thermometer and so in one embodiment of my invention I movably ymount said thermometer `within the casing so that the tampererwill `not know where to tap and the chances of 4his successful tapping are reduced to a minimum and in another embodiment of my invention` vI resilientlyg'mount said thermometer Within the casing so that- -no tapping thereofmay "cause the maximum/and minimum indicating means to move.

A further objectief my invention ris to provide a novel; type of tamper-proof maximum and minimum thermometer adapted for any use in transportation or otherwise.

Theseand such other objects of my invention as mayfhereinafter appear will be best understood from 'a .description .of' the accompanying drawing which illustrates embodiments thereof;

one embodiment of my invention employing :a maximum and minimum thermometer rotatably mounted within 'a sealed casing :forming amagnetic screen, a portion of the casing being bro- `kenaway to show the thermometer andshowing the casingcover in closed sealed position.V

Fig. 2- isa front elevation of the' embodiment fof my invention shown-inig.4 1 with the V'cover pivoted to yopen position and the thermometer rotated to a vertical position.

Fig.'3 is a vertical sectional view. taken through the embodiment of my Yinvention shown in Fig. `1 with the thermometer rotated vto a vertical `position `and shown in elevation. f

-Eig.4 isfa front elevationof la diierent enr-- bodiment of my invention employing :a easing constructed of material forming `a similar magnetic screen with the'ends of the thermometer re silientlymounted within the casing.

Fig. 5 isa vertical sectional View of the eml20 bodimentrof 'my invention shown in Fig. 4,also showing the lthermometer in elevation.

In the -d`raW-ing, wherein ,like characters of 'reference indicate like parts throughout, l0 generally 'indicates my invention, which as stated hitherto, includes, a vmaximum and minimum `thern'iometer l2. -Whi1e anyl type'of maximum .and minimum thermometerV may be employed,V most usualgtypes include a `U -shaped vacuum tube I4 having the maximum limb Iliand the 30 `mum limb I8 -with va heat expansionV bu1bd20 for the expansive thermometric liquid v22":whicl1 con-` trols in the usual manner the height -of the jin- I dicating thermom-etricV liquid 24 in eachglimb.

comprising slugs of a magnetizable metal, such as Ysteel, or iron,V which areAvso rlight that they vmay Abe'carried to respective Amaximum sind minimum. indicating positions.

A 'I'hese indicating means ,26 and28 normally ride Von thesurfa'ce of Y'theV thermometric indicating liquidy 2,4 Vto be V4moved totheir Vrespective maximum -andnlminimumwpositions thereby and whenyt-heL period for which-50 Y the respective maximum jand fminimum fread? ings are desired has expired, these indicating Y meansZG andY 2-8 have beenmovable backto pov sitions-floating on said thermometrlcindicating liquid by an externallyv applied magnet. ...55

A feature of my invention is to enclose a maximum and minimum thermometer within a casing constructed of a material capable of forming a magnetic screen to positively prevent movement of said indicating means by a magnet applied externally of said casing 30. The thermometer I1! may be removably contained within the casing 30 in any suitable manner, butin each embodiment of the invention shown, I provide a casing 30 having a body 34 and a removable cover 36 hingedly secured thereto and means 33 to seal the cover 36 in closed position to the body 34, or broadly speaking, means 38 to seal thecasing when completely enclosing the thermometer. If the casing 32, including its body 34 and cover 36, where employed, be constructed of a magnetic material, such as cast iron or steel, it will of itself form a magnetic casing screen to positively prevent movement of said indicating means by a magnet applied externally of said casing. In other words, the casing is made so magnetic as to positively prevent the application of external magnetism from moving the indicating means 26 or 28.

As stated means 38 are provided to seal the casing when completely enclosing the thermometer, namely, the means 38 to seal the cover 36 to the body 34 when in closed position, inthe embodiment shown said means comprising an eye 40 on the cover, an eye 42 on the body, a mounting eye 44 and a soft metal seal 46 comprising a piece of wire 43 which may be passed through the respective eyes 40, 42, and 44 and through suitable holes in a compressible soft metal disk 50 which may be compressed to bind the ends of the Wire therein, of any standard type, such as is employed in freight car seals, or meter seals.

As stated hitherto, another fault with maximum and minimum thermometers has been that the indicating means 26 an 28 may be moved within the tube I4 by tapping on the ends of the thermometer and my invention further relates to an improved type of means to prevent such movement which-I believe are novel, whether or not the casing of itself be constructed of a material forming a magnetic screen or otherwise. For this purpose, in the embodiment shown in Figs. 1-3, I rotatably mount the thermometer 32 on a suitable standard 52 on the casing body 34 by means yof the pivot pin 54. Thus if the casing 30, shown in Figs. 1-3 be tapped in just the right position the indicating means may be moved but just the right position comprises a very small percentage of the periphery of the cylindrical casing so that the chances of the indicating means being moved by tapping are reduced to a minimum.

An alternative type of means for preventing tapping on the ends of the thermometer from moving the indicating means 26 and 28 is shown in the embodiment shown in Figs. 4-5, in which means 60 are provided to resiliently mount said thermometer Within the casing 30 to prevent movement of said indicating means onrtapping said casing, in the preferred embodiment said means comprising helical springs 60 interposed between and if desired as shown, positively connecting the ends of said thermometer 32 and the casing end walls.

It is thus apparent that I have provided a substantially tamper-proof maximum and minimum thermometer, not only proof against external tapping manipulation, but also if desired, proof against external magnetic manipulation, particularly adapted in the manner previously `explained, for use in the brooding of chicks.

A ried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions floating on said Ythermometric indicating liquid means by an externally applied magnet, a casing for removably enclosing said thermometer constructed of magnetic material to provide a magnetic casing screen to positively prevent movement of said indicator means by a magnet applied externally of said casing, means to seal the casing when completely enclosing the thermometer and means to movably mount said thermometer within the casing.

2. As a new article of manufacture, a maximum and minimum thermometer having vacuum tube means having maximum and minimum limbs and containing thermometric indicating liquid means and magnetizable indicator means carried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions iioating on said thermometric indicating liquid means by an externally applied magnet, a casing for removably enclosing said thermometer constructed of magnetic material to provide a magnetic casing screen to positively prevent movement of said indicator means by a magnet applied externally of said casing, means to seal the casing when completely enclosing the thermometer and means to rotatably mount said thermometer within the casing.

3. As a new article of manufacture, a maximum and minimum thermometer having vacuum tube means having maximum and minimum limbs and containing thermometric indicating liquid means and magnetizable indicator means carried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions floating on said thermometric indicating liquid means by an externally applied magnet, a casing removably enclosing said thermometer constructed of magnetic material to provide a magnetic casing screen to positively prevent movement of said indicator means by a magnet applied externally of said casing, means to seal the casing when completely enclosing the thermometer and means to resiliently mount said thermometer Within said casing to prevent movement of said indicator means on tapping of said casing, comprising a helical spring interposed between each end of said thermometer and each casing end wall.

4. As a new article of manufacture, a maximum and minimum thermometer having vacuum tube means having maximum and minimum limbs and containing thermometric indicating liquid means and magnetizable indicator means carried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions'floating on said thermometric indicating liquid means by an externally applied magnet,

a casing removably enclosing' said thermometer 75V constructed of magnetic material to provide a magnetic casing screen to positively prevent movement of said indicator means by a magnet applied externally of said casing, means to seal the casing when completely enclosing the thermometer and means to resiliently mount said thermometer within said casing to prevent movement of said'indicator means on tapping of saidv casing.

5. As a new article of manufacture, a'maximum and minimum thermometer having vacuum tube means having maximum and minimum limbs and containing thermometric indicating liquid means and magnetizable'indicator means carried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions floating on said thermometric indicating liquid means, a casing removably enclosing said thermometer, means to seal the casing when completely enclosing the thermometer and means to rotatably mount said thermometer within the casing.

6. As a new article of manufacture, a maximum and minimum thermometer having vacuum tube means having maximum and minimum limbs and containing thermometric indicating liquid means and magnetizable indicator means carried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions iloating on said thermometric indicating liquid means, a casing'removably enclosing said thermometer, means to seal the casing when completely enclosing the thermometer and means to resiliently mount said thermometer within said casing to prevent movement of said indicator means on tapping of said casing, comprising a helical spring interposed between each end of said thermometer and each casing end Wall.

v7. As a new article of manufacture, a maximum and minimum thermometer having vacuum tube y means having maximum and minimum limbs and containing thermometric indicating liquid means and magnetizable indicator means carried by the thermometric indicating liquid means in each limb to the respective maximum and minimum positions therein movable back to positions oating on said thermometric indicating liquid means, a casing for removably enclosing said thermometer, means to seal the casing when completely enclosing the thermometer and means to resiliently mount said thermometer Within said casing to prevent movement of said indicator means on tapping of said casing.

MAX A. CAMPBELL. 

